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Table 16 — Compressor Stages and Circuit Cycling, Example 1
TOTAL
STAGE
Cir.
CAP.
Cap.
0
0
1
8
24
2
11
33
3
22
33
4
33
33
5
44
66
6
55
66
7
66
66
8
77
100
9
88
100
10
100
100
LEGEND
MLC — Minimum Load Control
TOTAL
STAGE
Cir.
CAP.
Cap.
0
0
0
1
8
24
2
11
33
3
22
66
4
33
100
5
44
100
6
55
100
7
66
100
8
77
100
9
88
100
10
100
100
LEGEND
MLC — Minimum Load Control
In Example 3 (Table 18), assume the following configurations
are in place:
Configuration
UNIT
HGBP=1 . . Minimum Load Control
installed and enabled for Start-Up Only
Configuration
OPTN
LOAD=0 . . .Equal Circuit Loading
Configuration
OPTN
LLCS=2 . . . . . . . . . Circuit B Leads
Since Circuit B has been selected, it will be the lead circuit.
Within the circuit, compressor B2 has the lowest wear factor
and will start first with Minimum Load Control ON. The next
stage will turn OFF the minimum load control. Stage 3 will
start another circuit because of the Equal Circuit Loading
configuration. Comparing Circuit A and C, the circuit with the
lowest average wear factor is Circuit A, and the compressor
with the lowest wear factor is A3. The next stage will be a
circuit C compressor. The process continues until all compres-
sors are ON. See Table 18.
In Example 4 (Table 19), assume the compressor starts and
run hours are the same as in the first example and the following
configurations are in place:
Configuration
UNIT
HGBP=1 . . Minimum Load Control
installed and enabled for Start-Up Only
Configuration
OPTN
LOAD=1 . . Staged Circuit Loading
Configuration
OPTN
LLCS=3 . . . . . . . . . Circuit C Leads
CIRCUIT A
MLC
A1
A2
A3
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Table 17 — Compressor Stage and Circuit Cycling, Example 2
CIRCUIT A
MLC
A1
A2
A3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
CIRCUIT B
Cir.
MLC
B1
B2
Cap.
0
0
0
33
X
33
X
33
X
66
X
66
X
66
X
100
X
X
100
X
X
NOTES:
1. Total Cap. (Total Unit Capacity) and Cir. Cap. (Circuit Capacity)
are approximate percentage values.
2. Example is to determine minimum load control, staged circuit
loading, and automatic circuit select.
CIRCUIT B
Cir.
MLC
B1
B2
Cap.
0
0
0
0
0
33
X
66
X
100
X
X
100
X
X
100
X
X
100
X
X
NOTES:
1. Total Cap. (Total Unit Capacity) and Cir. Cap. (Circuit Capacity)
are approximate percentage values.
2. Example is to determine minimum load control, staged circuit
loading, and automatic circuit select.
Since Circuit C has been selected, it will be the lead circuit.
Within the circuit, compressor C2 has the lowest wear factor
and will start first with Minimum Load Control ON. The next
stage will turn OFF the minimum load control. Stage 3 will
start a compressor in the same circuit because of the Staged
Circuit Loading configuration. Compressor C3 has the next
lowest wear factor and will be started next. Compressor C1
will be next to start. Since all compressors in Circuit C are ON,
the next stage will start another circuit. Of the remaining cir-
cuits, Circuit A has the lowest wear factor, and the compressor
with the lowest wear factor is A3. All of the Circuit A com-
pressors will be started in the same manner as Circuit C. Once
all Circuit A compressors are ON, then Circuit B will be start-
ed. The process continues until all compressors are ON. See
Table 19.
If the circuit capacity is to be reduced, the compressor with
the highest wear factor will be shut off first (in most cases).
With Equal Circuit Loading, stages will be removed from each
circuit, following the same criteria used in the loading
sequence, but in the opposite order. Shown in Table 19 based
on the current wear factor in the opposite to the loading
sequence shown above, the compressor with the highest wear
factor will be removed first. When Staged Circuit Loading is
selected, the capacity from the last lag circuit will be removed
first.
21
CIRCUIT C
Cir.
B3
MLC
C1
Cap.
0
0
0
0
33
33
X
33
X
66
X
66
X
66
X
100
X
CIRCUIT C
Cir.
B3
MLC
C1
Cap.
0
0
0
0
0
0
X
0
X
0
X
33
X
66
X
100
X
C2
C3
X
X
X
X
X
X
X
X
X
X
X
C2
C3
X
X
X
X
X
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